Mail Archives: djgpp/1999/04/20/19:35:51
Eli Zaretskii wrote:
>
> On Thu, 15 Apr 1999, Mark Usher wrote:
>
> > How can I be sure of reserving exactly 8 bytes at the start of my event
> > handler that I pass with go32_dpmi_allocate_real_mode_callback_retf ?
>
> I have never tried anything like that, but I think this is
> impossible. The first bytes of the callback are used by the callback
> code itself, and the callback is created by the DPMI server.
>
> So the only feasible way to achieve this would be to bypass the
> callback and _go32_dpmi_allocate_real_mode_callback_retf entirely, and
> instead to write your own real-mode handler in assembly.
Someone else suggested the idea, which I think makes a lot of sense, of
allocating a tiny buffer which has the magic 8 bytes followed by a jmp.
The opcode for `jmp far' is 0xea. Then 'seg:ofs' as a longword.
--
Nate Eldredge
nate AT cartsys DOT com
- Raw text -